The Biostatistical and Analytic Core (BAC) will provide advanced statistical and analytic support for all experimental projects within the Program Project Grant (PPG) and will be instrumental for achieving the overall aim of quantifying the relative contributions of sleep loss and circadian disruption on metabolism in healthy older people. To achieve this overall aim, the BAC will analyze data collected in the proposed PPG, as well as data across studies from the proposed, current, and previous PPGs and other studies conducted in the same facilities by PPG investigators. The integrative power of the PPG will therefore enable the BAC to extend the work of the individual experimental Projects by using data from multiple projects. This integration will allow more powerful and detailed statistical analyses, as well as cross-experiment analyses and comparisons that will enable stronger conclusions to be made about the effects of sleep loss and circadian disruption on physiology, metabolism and autonomic function in humans and rodents. The BAC specific aims are: (SA1) To conduct the primary and secondary statistical analyses for each of the individual projects within the PPG using state-of-the-art statistical and analytic methods for evaluating the specific aims of each individual project; (SA2 and SAS) To quantify the effects of sleep loss and circadian disruption, their interaction, and recovery from these exposures on various metrics of metabolism (SA2) and autonomic function (SAS) by using longitudinal analyses and by analyzing and comparing data across different experimental protocols. Analytic and statistical methods - along with the bio-mathematical models developed by the Analytic Cores within previous PPGs - have been used to design and to analyze most experiments in the Brigham and Women's Hospital (BWH) Division of Sleep Medicine (DSM). New methods are required because of the longitudinal, correlated, and frequently non-normal distributions of the data collected. Appropriate statistical and modeling techniques determine whether an intervention has a significant effect, and to enable extraction of additional information from previously collected data. Therefore, the BAC will support and greatly extend the results of the PPG experimental work.